Cyclic process of extracting metals from cupriferous materials.



. A. DAVID. CYGL-IG PROCESS 0FV EXTRACTING METALS FROM GUPRIFIJROUS MATERIALS.

APYLIUATION FILED JULY 9, 1913.

Patentedct. 7, 1913.

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'ALBERT D'avr'n, 'or BROOKLYN, ivi-:W YORK, As's'rcivon 1ro iarnnnivn onnsann PATENTS o.,.or1vsw YORK, u. fr., 'a conrona'rroiv or MAINE.

cYoLIc rnoonss or'nx'r'nncrnve nisransraoiir Icurairrn'ous MATERIALS.

T 0 all -i/:zom'z' may concern Be it known that I,"\ iii.nrn r\ Davm, a citizen of the United States. residing at Brooklyn, in the county of Kings and Stateof New York, have invented certain new and useful Improvements in Cyclic-Processes of Extracting Metals from Cupriferous Materials, of'which the following is a specilication.

The present invention is a' process of extractinglmetals from cupriferous materials, such for example as-suld, oxid. carbonate and silicate ores containing silver, gold and iron.

The process comprises thesteps of leaching the ore wit-h a solution of a ferric salt, preferably the chlorid. precipitating the dissolved copper by finely-divided electrolytic iron, and electrolyzing the residual solution under such conditions that the solvent salt is reconverted to the ferric form and excess iron is simultaneously deposited in suitable form for use as the p'ecipitant. Certain auxiliary reagents are preferably employed for the purpose of facilitating both the electrolysis and the leaching. One of these reagents is a neutral or non-acid chlorid which will promote the leaching by bringing the silver (and copperl'. into solution. and will,

promote the electrolysis by ionizing and increasing the conductivity of the spent leachliquor without reacting on the deposited iron, for example.' a 'chlorid. of an alkali metal. A second auxiliary rea-gent is a free acid 4which will promote 4the electrolysis by increasing the conductivity of the solution and preventing. the vdeposit of basic compounds. and" willvpromote the leaching by neutralizing or decomposing' certain constituents of the ore, thereby protecting and As such acid, hydrochloric vis preferred.

as Well as vbeing introduced in tc 'the anode compartments of the 'electrolytic cells as described below. A third auxiliary reagent is `a-solublesulfate,l for example sodium -sulfate, acting to increase the electrolytic conductivity in regeneration, and to lconserve chlorin in leaching. by decomposing anyT calcium or similar chlorid formed and precipitating an insoluble sulfate.

In carrying out the electrolysis. ,adiaphragm cell is preferably `employed. with insoluble anodes, and cathodes preferably ot Spcccaton of Letters Patent. application sied July 9', 1913. seri'aiivo. 775.166.

Such acid mayv be added directlyto the leaching solution,

iron, the solution beingtl'elivered from the copper-precipitation' vessel, or filter, into the cathode compartment, wherein the excess iron is deposited, and thence into the anode compartment, wherein the free acid may be added and the reconversion of the `solvent to the ferrie form is effected. The electrolysis is carried out under conditions which promote oxidation at. the anode. Both electrolytic products.' the regenerated solution and the vfinely-divided iron, are used in r peating the processen another charge df ore, the process thus being rendered cyclic or continuous.

For the purpose of illustration only, the

certain ore is given: The ore. an oxidized au'ltid carrying copper, iron. silver 'and gold. -rushedfto pass a sieve of twelve meshes to the linear inch. was leached with an aqueous solution containing, by weight, about four per cent. of ferrie chlorid, two per cene-'0f sodium chlorid. and three per cent. of commercial hydrochloric acidv of :'207 Baume, the solution having a specific gravity of about 1.05 and a temperature ofabout C./ The ore was agitated vduring the leaching andv hot .air was blown throughA the solution. The free acid-acted to assist in decomposing the copper compounds and other soluble elements in the ore. The hot air acted to heatf the solution and vto oxidize the metallic copper andtherebv 'facilitate its solution. The' sodium chlorid acted to promote solution of the silver chlorid and cuprous chlorid produced b v the action of the ferrie chlorid.

The resulting solution was then treated with a sutiici'ent amount of nely-divided electrolvtic iron produced as hereinafter de scribed. thereby precipitating all of Athe cop-v per. silver and gold therein, and neutralizing anv residual hydrochloric acid. Such electrolytic iron is a highly. active precipitant forcopper. owing partly vto its finelydivided form. and probably Aalso in part to its ,characteristics as a product of electrolysis. The spent. leach-liquor.- separated from the precipitated metals andat. atmos- Patenteu oem, 1913.

70k following example of actual practice on aiy pheric temperature, was then run into a ,m5

plurality of electrolytic cells each'having a number of parallel cathodecompartments and diaphragms consisting of rectangular canvas bags. The cathodes were sheets-of thin iron. within the bags. and the anodes were vertical bars of graphite, between and outside the bags, and about two inches from the cathodes. Electrolysis was effected by a unidirectional current having anv electrodepotential-ditlerence of'about three volts, the resulting cathode currentdensity being about 0.25 amperes per square inch. After both compartments of the cells had been giitiglly iilled'yviththespent liquor, the reilaindenwas ed to the'bottom of the bags, t e'vertlowing vinto the Aseveral anode coinA ents. ,--Hydrochloric acid Was, gra tial "addedf'outside the bags, until a totaliof three vper-cent: had been supplied. The'excess iron vWasy deposited'on the cath-4 odes" in .avery 'ixiely-divided form, falling to the bottoln'of the bags or being 'easily detached fromtle' iron sheets,l any Oxy-com# lpounds of ironjbeing redissolv'ed inthe acid solution.-1 [The: ferrous chlorid was largely co vrted intolfe'rri'c chl-oridat the anodes, anf, ftheforiginal'f leaching solution and pre- -cipi'tantt'ivei'ethereby re-provided.

Whilfallf-the ferrous salt may beelectrolyticallyconverted' intothe ferric form, it is'fusually preferable not to carry the regenii'atioiito this limit.- When the ore con taisiconsiderable amount of iron in solution fand-'a' 'portion of it must be removed from time. to time. By leaving a', certain amount-of ferrous salt in the regenerated solution', this salt dissolves copper in the orf`with the precipitation of an equivalent amount of iron, which remains inthe tailings as an insoluble hydroxid or basic com pound, the amount of--iron thus automatically removed from the solution in 'the step of leaching being regulated in the step ofregenerating.

It the ore contains littlev or no soluble iron, the solution slowly becomesV depleted of this metall Under this and other conditions, it may be desirable to supplement thelectrolyticl iron used as a precipitating agent by 'iron from an outside source. The electrolytic. iron is in a state of extremely line division, and sometimes undergoes par tial oxidation -before it is used, but this does not interfere with its use' as a precipitant.

During the leaching, cupric chlorid may be formed 4as ,an intermediate product and may then itself act as a solvent for copper 'in the ore.

Reference'is made to the accompanying drawing wherein the -figure 1s a diagram illustrating the several steps of a preferred.-

embodiment of the process. f

I claim:

l.' The cyclic processl of extracting metals from cupriferous materials, which consists in leaching the material with a solution c0n taining a ferrie salt, precipitating the dissolved copper by electrolytic iron, electrolyzing the spent solution under conditions to precipitateiron inhighly reactive form and to regenerate the solvent, and repeating thesel operations with other charges 'ott' material, utilizing said regenerated solvent as leaching agent.

2. The cyclic process of extracting metals from. cupriferousl materials, which consist in leaching the material with a solution containing erric chlorid, precipitating the .dis-- solved copper by electrolyti'c iron, electrolyzringlthe spent solution under conditions to precipitate iron in' highly reactive rforni and to regenerate the, solvent, `and repeating these operations with other charges of material, utilizing said regenerated solvent as leaching agent.

3. The cycl" i 80 process of extracting metalsv .from cupriferous materialscontaining silver, which consists in leaching the material `with a solution containinga fel-'ric salt and a solvent of silver chlorid,lprecipitating the dissolved copper by electrolytic iron, electrolyzing the spent solution `under conditions to precipitate iron in .highlyreactive form'and to regenerate.the solvent,.and repeating these operations with other charges of material, utilizing said regenerated soln vent as leaching agent. :ble form this metal accumulates in the solu- 4;. The cyclic process of extracting metals from cupriferous materials containing silver, which consists in leaching thematerial with a solution containing J ferric c hlorid and sodium chlorid, preci itating the ldissolved copper by electrolyti iron, electrolyz-v ing the spent solution under conditions to precipitate iron inhighly reactive form and to regenerate the f solvent, and repeating these operations With Vother charges of material, utilizing said regenerated solvent as leaching agent.`

5. The cyclic process of extracting metals 105 from cupriferou's materials containing silver, which consists in leaching the` material with a solution containing a -ferric salt, a solvent of silver chloridand a freev acid, precipitating the dissolved copper by electrolytic iron, electrolyzi'ng the spent solution under conditions to precipitate iron in hi hly reactive form and to regenerate the so vent, and repeatingthese operations with other charges of material, utilizing said regenerated solvent as leaching agent.

6. The cyclic process of extracting metals from cupriferous materials containing silver, which consists in leaching the 'material with a solution containing a. ferrie salt, a 120 solvent of silver chlorid, afree acid and a. soluble sulfate, precipitating the` dissolved copper by electrolytic iron, electrolyzing the spent solution under conditions toprecipi- Vtate iron in highlyr reactive form and to regenerate the solvent, and repeating .these operations with other charges of material, utilizing said regenerated solvent as leachin-g agent.

7.- The cyclic process of. extracting metals 13o from cupriferous materials Containing si1- sdium chioriy hydrochloric acid and s0- 've1', which consists in leaching immaterial {iium sulfate, precipitating file dissoived with a solution containing. ferrie hlorid7 copper by electi'oiynic iron., eiect'oiyzing the vsodimm chloid and hydrochoric acid, prespent solution under conditions to precipin "cipitating the -dissolved copperA by electro tait@ iron in highly reactive form and to re- '20 lytic iron, electrolyzing the spent solution generate the solvent, and repeating these under conditions to vpiiezzipiaie iron in operations'with other charga @f materiaL highly reactive oi'mI and to regenen-twill@ utilizing said rgenemed soven :is leachsolvnt, and, repeating these operations with ing agent.

lo Aothezj-chaacges of maerial, utiliziiig said re In testimony 'whereof I filmx my signaure 25 generated solvent as leaching agent in presence of 'two Witnesses,

8. The cycib process of extractingmegzs MSE-ERT @AVID v from cupi'ifel'ous matiiais containing sii W'inesses: Ver9 which.' cnnsists in leaching the matezii TL, l with a. soun containing ferrie Chiarinil E, REN-SHAW' BUSH. 

